Vernier rheostat



May 18, 11926. 1,585,347

o. F. HEsLAR y VERNIER RHEOSTAT Original Filed 001.750, 1922 ,8 P@ l l. Flq. l /16 2e zo z8 16M.. I o

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Patented May 18, 1926.

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OLA F. HESLAR, OF MARION, INDlANA, ASSIGNOR TO INDIANA MANUFACTURING & ELECTRIC CO., OF MARION, INDIANA, A CORPORATIGN OF INDIANA.

VERNIER RHEGSTAT.

Application filed October 30, 1922, Serial No. 597,846.

This invention relates to a vernier rheostat, particularly adapted for use in connection with a. radio receiving set.

ll'leretofore the resistance units or rheostats have been so constructed that there is an appreciable difference in resistance between succeeding coils of the resistance wire, whereby said resistance could not be uniformly and variably controlled. lt has usually been necessary, therefore, in constructing a Vernier rheostat to provide a second auxiliary adjustment for ena-bling such difference in resistance to be compensated.

VThe main feature of this invention is to construct a rheostat of a simple and compact arrangement for eliminating the necessity of providing an auxiliary resistance control to malte it a vernier rheostat. rlhis is accomplished by providing a resistance coil with a VSliding Contact member so arranged as to be engageable with any point thereon. lhe length of the resistance winding may be ever so slightly variedL by the slight variation of the point of contact thereon so as to enable a fine adjustment of the resistance without the use of an intermediate auxiliary control. Such a resistance unit as is contained in this type of rheostat is uniformly variable throughout and thereby permits a fine variation of resistance without necessitating compensation for the difference in resistanceof the usual coils or loops.

ln connection with a radio receiving circuit, this rheostat allows an absolute control over the flow of electrons in a vacuum tube which does not necessitate a change in wave length or frequency which is necessary to compensate for the resistance between the coils or loops of the usual type of rheostat. In tuning a receiving` instrument for the reception of certain wave lengths, such tine adjustment may be had by means of this type of rheostat as to Completely control the flow of electrons so as to eliminate the necessity of adjustment by varying the condenser, vario-coupler or varioineter, and also with a single adjustment rather than the double adjustment necessary in such a. construction as is embodied in a Vernier filament controlled rheostat. This permits of better results in the receiving circuit, inasmuch as the variable condenser, variometer or variocoupler may be concentrated on adjustment to the wave length, instead of being ad- Renewed February 17, 1926.

justed to compensate for variations of resistance in the rheostat.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

in the drawings, Fig. l is a plan view of -Jthe rheostat mounted upon an instrument the outer end thereof by means of the screw 18, said knob carrying the usual dial let. Secured to the inner wall of the board 10, there is a. supporting disk l formed of any suitable insulating material, such as hard rubber or fiber.

lilounted on the inner end of the shaft 1l and keyed thereto, there is a rotating drum 1G adapted to be rotated by the shaft ll up` on the turning of the knob l2. rlhe instal Contact dist ll is embedded in the drunr` 16 which is also made of an insulating material, such as hard rubber or liber, and is secured on the outer face thereof by the pins i8. The end of the shaft ll is insulated from the plate l? by the washer 19 which is also made of suitable insulating naterial. The periphery of the drum 16 is provided with spiral grooves or screw threads in which there is wound a resistance wire 20, said wire being wound about the periphery of said drum in the grooves formed by said screw threads. The drum being made ef insulating material, and the windings or loops of the resistance wire being separated by the screw threads, each loop will be insulated from the other. One end of the wire is secured in position by the pin 2l having a head 22, and the other end of said wire is adapted to extend radially into said drum through a suitable openingv bored therein to the plate 17 where it extends to a hole drilled therein and is soldered in position. For further securing the last mentioned end of the Wire in place, it is wedged in the radial hole et the drum hy the pin 28 having n head 9A.

Rigidly mounted upon the Supporting disk l5, there ere brackets 25 ard 26, seid hrnczlete being insulated trein @sich othei1 by Seid dis-ii. Mounted on the bracket 25, there is :i conte t erin secured in position by the holt and nuts i528 which comprises one ot the terminals to which lead Wire is secured. The tree end et the Contact erin i7 is bi'uicated, ne shown in Fig. 3, so that it `Yieldin fly eng the Contact plete 17 through which it is :iilueys in electrical contact with the outer end o1 the ree: tane Wire 20. Pivotelly mounted on the hre/liet 2i), there :i i'iiovzihle Contact erin 28 Laying :in inwardly exteneing pointed linger The anni LS in the 'forni of e plete spring which teper to the poinf Wl'iieh is oonstnntly in eng; ith the insistence Wire L) under ii-ing tension. Said arm 28 is piif'otnlly mounted et its bese upon the h ufhet Sii by the holt and nuts 30 which torni the other tei'niinel i'i the circuit.

.ln operation, upon Conn Aeeting the rheostat in the circuit, the terininais 12S and are secured to the leed wire-s, whereby the current will through the teriniiril 128, Contact erin 2T and plate l? to the inner end of the resistzniee wire 20. t will then puse through "he wire about the periphery ot the drum to the point of engagement therewith hy the finger QS), through the n'iorzrhle Contact arm 28, the te niiual BO and the leed Wire attached thereto. it will he obvious that the resistance ot the rheostat will depend upon the length of that portion eif t nee Wire through .'vhieh it passers. bueh resistance may be 'Varied by turiiing the knob l2 Whieh will rotate the drinn 16. Such rotation et the drum with reepeet to the mov: ble n'nn which is l to the stationr f part oit @euse the engaging linger guided t threat-like he registi'` :'29 there peripher: Contact i nie nievenient W1; to nieve beck und .torti aeree-s the surface o' the drinn 'troni the position shown in Fig. l to that shown in. Fig. L. When the inger reaches either end of the. wire, it fill he stopped oy its engagement with the heads 22 und oit the pins :2l und 2?). This Contact `"ith seid heide liinits the rotary movement ot the drinn and the lateral niow'enieut ot the erin, so that it cannot more out ot the n constant ri grooves and lose Contact with the resistance Wire.

Contact or coil to coil. 1.5

The .invention c unned is:

l. A. riieostut mounted to he in i :otutnh i'ornief. uhm

e vound in Suid grooves. one eine l one end ion et' n thereon pivotal inol'nt oif Contact l rheostet adapted to 13e i'iiouuted on nary panel, comprising n rotatable druin having; Spiral grooves formed about the periphery thereof, ineens for rotating' seid druin, a resiste-.nee Wire Wonne in fr' grooves, an annuler Contact ring OTCOTQS thei on one side of sind d in und conne@ 'ed u' 100 one end of Suid reszitunee wire, u lr adapted to eontaet with seid ring, hind no 'connected with seid hr eh, :i mul bn pest mounted onv said panel, zv u i" Contact finger pivi'itzilly mounted ou 105 s; f oi d bindingl post and e\ end' i ,.phei'lfv et @uid di n1 hu L Sui rui end extending into sane gageinent with Said Wire tion ot Suid lru groove-L'. thereon t` '5 its piroiol n'iounting .-o am to riry tirn or Contact thea-ot with sid n' lu witness; whereof, l hure here fixed my signature.

ULA F. HGSLA 1. 

